Looking for design patterns offered in Android to alert users of required fields like in a form? for both pre and post validation. For example, a website registration for often requires name, password, etc as required fields. Many times the required fields are indicated with a different colored text input field. In addition, if a user misses a required field and presses the save button a pop up might alert the user or the focus might change to the field. Does anyone know the different design patterns offered by Android? Thanks.